Impregnated cathode and its preparation method

Abstract

The present disclosure provides an impregnated cathode, which relates to the field of hot cathodes and includes a sponge substrate impregnated with an emission substance, and a texture layer formed on the surface of the sponge substrate, with a plurality of protrusions on the texture layer. The present disclosure has the effects of increasing the cathode emission current density and reducing the evaporation rate of alkaline earth metals.

Description

Technical Field

[0001] The present disclosure relates to the technical field of hot cathodes, and in particular to impregnated cathodes and their preparation methods. Background Art

[0002] Microwave vacuum electron technology is widely used in radar, satellite communication, electron accelerators, global positioning, controlled thermonuclear fusion, and high-power microwave weapons for future military frontiers.

[0003] The cathode for electron emission is the core part of microwave vacuum electron devices. The performance of the electron emission cathode directly affects the output performance and life of the microwave source, and further affects the performance and life of radar and high-power microwave sources. Therefore, researching high-performance new cathodes that meet high-power and broadband microwave sources is of great significance for promoting the development of technologies such as high-power microwave vacuum electron devices.

[0004] With the further improvement of the requirements for the quality of electron beams in microwave devices, the requirements for cathodes are also getting higher and higher. Currently, the cathode emission current density applied in microwave vacuum electron devices is relatively low and cannot meet the requirements for manufacturing high-performance microwave vacuum electron devices. Summary of the Invention

[0005] In view of the above problems, the present disclosure provides an impregnated cathode and its preparation method to improve the problem of relatively low cathode emission current density.

[0006] One aspect of the present disclosure provides an impregnated cathode, including: a sponge substrate impregnated with an emission substance; a texture layer formed on the surface of the sponge substrate, and the texture layer has a plurality of protrusions.

[0007] Optionally, the material of the sponge substrate is any one of platinum, ruthenium, or platinum-ruthenium alloy.

[0008] Optionally, the sponge substrate is prepared from powders of platinum, ruthenium, or platinum-ruthenium alloy.

[0009] Optionally, the powder particle size of platinum, ruthenium, and platinum-ruthenium alloy is 1 μm to 10 μm.

[0010] Optionally, the texture layer is formed by ion beam bombarding the surface of the sponge substrate.

[0011] Optionally, the protrusions are in the shape of burrs, the diameter of the top of the protrusions is 0.1 μm to 1 μm, and the height of the protrusions is 0.1 μm to 1 μm.

[0012] Optionally, the emission substance is aluminate.

[0013] Optionally, the emission substance is one or more of barium aluminate or calcium barium aluminate.

[0014] Another aspect of the present disclosure provides a method for preparing an impregnated cathode, including: performing ion beam bombardment on the surface of a sponge substrate to form a textured layer on the surface of the sponge substrate

[0015] Optionally, when performing ion beam bombardment on the surface of the sponge substrate, a tungsten target is used.

[0016] At least one of the above technical solutions adopted in the embodiments of the present disclosure includes at least the following beneficial effects:

[0017] A sponge substrate is prepared using platinum, ruthenium, or a platinum-ruthenium alloy with an ion sputtering rate higher than that of tungsten. After ion beam bombardment on the surface of the sponge substrate, a textured layer will be formed on the surface of the sponge substrate. The textured layer has multiple burr-like protrusions, increasing the emission surface area of the impregnated cathode, thereby improving the emission current density of the impregnated cathode;

[0018] The formed textured layer enables the impregnated cathode to have strong adsorption performance, reduces the evaporation of alkaline earth metals and their oxides in the impregnated cathode, and improves the quality of the impregnated cathode;

[0019] The method for preparing the impregnated cathode is simple and convenient for popularization and utilization. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] To more fully understand the present disclosure and its advantages, reference is now made to the following description in conjunction with the accompanying drawings, in which:

[0021] Figure 1 Schematically shows a schematic diagram of the overall structure of the impregnated cathode provided by the embodiments of the present disclosure;

[0022] Figure 2 Schematically shows a flowchart of a method for preparing an impregnated cathode provided by the embodiments of the present disclosure;

[0023] Figure 3 Schematically shows a schematic diagram of the structure of ion beam bombardment on the surface of the sponge substrate;

[0024] Figure 4 Schematically shows a schematic diagram of the morphology of the platinum sponge substrate after surface treatment provided by the embodiments of the present disclosure.

[0025]

DESCRIPTION OF THE REFERENCE NUMERALS

[0026] 1 - sponge substrate; 2 - emission substance; 3 - textured layer; 31 - burr; 4 - cathode cylinder; 5 - cathode heater; 6 - ion beam; 7 - tungsten target; 8 - cathode to be treated. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] To make the objectives, technical solutions, and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to specific embodiments and the accompanying drawings. Apparently, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0028] The terms used herein are merely for describing specific embodiments and are not intended to limit the present invention. The terms "including", "comprising", etc. used herein indicate the presence of the described features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0029] An embodiment of the present disclosure provides an impregnated cathode.

[0030] Figure 1 A schematic diagram showing the overall structure of the impregnated cathode provided by the embodiment of the present disclosure is shown.

[0031] Referring to Figure 1 , the impregnated cathode may include: a sponge substrate 1 and a texture layer 3.

[0032] The sponge substrate 1 is impregnated with an emission substance 2; the texture layer 3 is formed on the surface of the sponge substrate 1, and the texture layer 3 has a plurality of protrusions.

[0033] Specifically, a cathode cylinder 4 is provided at the bottom of the sponge substrate 1, and a cathode heater 5 for heating the sponge substrate 1 is provided inside the cathode cylinder 4.

[0034] It can be understood that the cathode heater 5 can heat the sponge substrate 1.

[0035] According to the embodiment of the present disclosure, the sponge substrate 1 is prepared from powders of platinum, ruthenium, or platinum-ruthenium alloy. The powder particle sizes of platinum, ruthenium, and platinum-ruthenium alloy are 1 μm to 10 μm.

[0036] According to the embodiment of the present disclosure, the texture layer 3 is formed by bombarding the surface of the sponge substrate 1 with an ion beam 6.

[0037] It can be understood that under the condition that the texture layer 3 is formed by bombarding the surface of the sponge substrate 1 with the ion beam 6, the texture layer 3 and the sponge substrate 1 are integrally formed. By directly bombarding the surface of the sponge substrate 1, an impregnated cathode can be obtained, with convenient operation and easy promotion and utilization.

[0038] Among them, platinum, ruthenium or platinum-ruthenium alloy are all high-temperature resistant materials with an ion sputtering rate higher than that of tungsten. A textured layer 3 can be obtained by modifying the surface of the sponge substrate 1 with an ion beam 6. Since the sputtering rate of ions is closely related to the sputtering coefficient of the material, when ions with a certain energy bombard the surface of a material with a high sputtering coefficient, and at the same time a certain amount of another material with a low sputtering coefficient is deposited on this surface, it is possible to form a highly textured surface, and this textured surface presents protrusions with a certain spacing and height. Under the condition that the metal surface of platinum, ruthenium or platinum-ruthenium alloy is bombarded by ions, depositing a certain amount of tungsten atoms will form this texture. Because the sputtering coefficient of tungsten atoms is relatively low compared to platinum, ruthenium or platinum-ruthenium alloy, tiny aggregation regions of tungsten atoms are formed on the metal surface of platinum, ruthenium or platinum-ruthenium alloy. These tiny aggregation regions act as masks, while the surrounding platinum and ruthenium atoms are sputtered away relatively quickly by ions, thus forming a protrusion structure. Multiple protrusions increase the emission surface area of the cathode and improve the emission current density of the cathode. At the same time, multiple protrusions endow the impregnated cathode with strong adsorption performance, reduce the evaporation of alkaline earth metals and their oxides in the impregnated cathode, and improve the quality of the impregnated cathode.

[0039] For example, the sponge substrate 1 can be prepared from platinum powder with a powder particle size of 10 μm. It should be noted that using platinum powder with a powder particle size of 10 μm to prepare the sponge substrate 1 in the above embodiments does not limit the embodiments of the present disclosure. Any one of platinum, ruthenium and platinum-ruthenium alloy can be selected according to actual preparation work. At the same time, the powder particle size of the corresponding material can also be selected from 1 μm to 10 μm according to actual preparation work.

[0040] According to the embodiments of the present disclosure, the protrusions are in the shape of burrs 31, the diameter of the top of the protrusions is 0.1 μm to 1 μm, and the height of the protrusions is 0.1 μm to 1 μm.

[0041] It can be understood that the micron-level protrusions further increase the surface area of the sponge substrate 1, can further improve the emission area of the cathode, and improve the emission performance of the cathode.

[0042] According to the embodiments of the present disclosure, the emission substance 2 is aluminate.

[0043] According to the embodiments of the present disclosure, the emission substance 2 is one or more of barium aluminate or calcium barium aluminate.

[0044] For example, the emission substance 2 can be a mixture of barium aluminate or calcium barium aluminate. It should be noted that the embodiments of the present disclosure do not specifically limit the type of the emission substance 2. In actual preparation, the emission substance 2 can be selected from any one of aluminates according to actual needs.

[0045] Based on the above inventive concept, the present disclosure also proposes a preparation method for an impregnated cathode.

[0046] Figure 2 The flowchart of a preparation method of an impregnated cathode provided by an embodiment of the present disclosure is schematically shown.

[0047] Referring to Figure 2 , the method may include operations S101 to S104.

[0048] In operation S101, metal powder of any one of platinum, ruthenium or platinum-ruthenium alloy is sintered to form a porous matrix having a large number of micropores.

[0049] Wherein the powder particle size of the platinum, ruthenium or platinum-ruthenium alloy metal powder is 1 μm to 10 μm.

[0050] In operation S102, the emissive substance 2 is immersed in the porous matrix to obtain a sponge matrix 1.

[0051] In operation S103, the sponge matrix 1 is placed in an ion bombardment system, and the surface of the sponge matrix 1 is bombarded with an ion beam 6 to form a texture layer 3 on the surface of the sponge matrix 1.

[0052] Figure 3 The structural schematic diagram of the ion beam 6 bombarding the surface of the sponge matrix 1 is schematically shown.

[0053] Referring to Figure 3 , according to an embodiment of the present disclosure, when bombarding the surface of the sponge matrix 1 with the ion beam 6, a tungsten target 7 is used.

[0054] Figure 4 The morphological schematic diagram of the surface of the platinum sponge matrix 1 after surface treatment provided by an embodiment of the present disclosure is schematically shown.

[0055] Referring to Figure 4 , the preparation principle of the method is described as follows: The sponge matrix 1 is prepared by using platinum, ruthenium or platinum-ruthenium alloy with an ion sputtering rate higher than that of tungsten. After the surface of the sponge matrix 1 is bombarded with the ion beam 6, a texture layer 3 will be formed on the surface of the sponge matrix 1. The texture layer 3 has a plurality of burr 31-shaped protrusions, which increases the emission surface area of the impregnated cathode, thereby increasing the emission current density of the impregnated cathode. The formed texture layer 3 enables the impregnated cathode to have strong adsorption performance, reduces the evaporation of alkaline earth metals and their oxides in the impregnated cathode, and improves the quality of the impregnated cathode. The impregnated cathode prepared by this method not only has a relatively high emission current density, but also has a simple preparation process, which is convenient for popularization and utilization.

[0056] In the present invention, unless otherwise clearly defined or limited, terms such as "installed", "connected", "linked", "fixed", etc. shall be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection, an electrical connection, or capable of communicating with each other; it can be a direct connection, or indirectly connected through an intermediate medium, and can be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0057] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by terms such as "longitudinal", "length", "circumferential", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the subsystem or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention.

[0058] Throughout the drawings, the same elements are denoted by the same or similar reference numerals. When it may cause confusion in the understanding of the present invention, the conventional structures or configurations will be omitted. And the shapes, sizes, and positional relationships of the components in the drawings do not reflect the actual sizes, proportions, and actual positional relationships. Additionally, in the claims, any reference signs placed between parentheses shall not be construed as limiting the claims.

[0059] Similarly, in order to streamline the present invention and assist in understanding one or more of the various disclosed aspects, in the above description of the exemplary embodiments of the present invention, the various features of the present invention are sometimes grouped together into a single embodiment, figure, or description thereof. The description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0060] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Therefore, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0061] The specific embodiments described above further elaborate on the technical solutions of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for preparing an impregnated cathode, characterized in that, comprising: bombarding the surface of the sponge substrate (1) with an ion beam (6) to form a texture layer (3) on the surface of the sponge substrate (1); wherein, the emission substance (2) is impregnated in the sponge substrate (1), the texture layer (3) has a plurality of protrusions, and the texture layer (3) is integrally formed with the sponge substrate (1); the sponge substrate (1) is prepared from powders of platinum, ruthenium or platinum-ruthenium alloy.

2. The method for preparing an impregnated cathode according to claim 1, characterized in that, when bombarding the surface of the sponge substrate (1) with the ion beam (6), a tungsten target (7) is used.

3. The method for preparing an impregnated cathode according to claim 1, characterized in that, the powder particle sizes of the platinum, ruthenium and platinum-ruthenium alloy are 1 µm to 10 µm.

4. The method for preparing an impregnated cathode according to claim 1, characterized in that, the protrusions are in the shape of burrs (31), the diameter of the top of the protrusions is 0.1 µm to 1 µm, and the height of the protrusions is 0.1 µm to 1 µm.

5. The method for preparing an impregnated cathode according to claim 1, characterized in that, the emission substance (2) is aluminate.

6. The method for preparing an impregnated cathode according to claim 5, characterized in that, the emission substance (2) is one or more of barium aluminate or calcium barium aluminate.

Images